PRACTICAL ORGANIC CIIEMISTRV
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(2) The hydracids (HC1, HBr, HI), in which case the halogen
attaches itself to the carbon with the least number of hydrogen
ClIa.CH:CII.j + HI = CII;,.CIII.CH:!.
Propylt'iiL'. Isopopyl iod'de.
(3) The halogens (Cl, Br, I),
CII,:CII2 + Go = CI I,C1.C1I,G.
Ethylene. Ethylene chloride.
(4) Cone, sulphuric acid,
CIIo:CIU+(XS< = OoS<
X)ii " xoii
Ethyl hydrogen sulphate.
(.5) Hypochlorous acid,
ciL:Ciio -f- iioci = cri2on.cii2ci.
Potassium permanganate oxides the olefine, forming in the
first stage the corresponding glycol. By further oxidation the
molecule is decomposed by the parting of the carbon atoms at
the original double link,
CIIS.CII : CILj + IUJ + O = CLI.^CIIOII.Cn.,011.
Propylcue. I'ropyL'iie ylycol.
CIIa.CIIOLI.CllaOII -I- 20, = CII;,,COOir + CO, I 2lloO.
Alkylene chlorides and bromides with both halogen atom-,
attached to the same carbon are obtained by the action of
PC15 and PBrfj on aldehydes and kctones.
cii3.co.cn3 + pcia = cii:i.ca,cir:j +
Acetaldehyde.—The formation of aldehyde from alcohol
probably occurs by the addition of oxygen and subsequent
elimination of water,
CH3CMaOII + O = CII3.CII(OII)a = ClLj.CCUl I- II,<X
The aldehydes may also be obtained by the reduction of acid
chlorides and of anhydrides in some cases, but the method is
rarely adopted. Aldehydes can only be obtained directly from